Regulator system for pulp grinders



Mar 29 192 ch 7 w. M. BRADSHAW ET AL REGULATOR SYSTEM FOR PULP GRINDERS Filed July 20, 1922 Prime Hover qlius.

INVENTORS William H. Bradshaw, & Walter G. I!

ATTORNEY WITNESSES:

Patented Mar. 29, 1927.

UNITED STATES PATENT OFFICE.

WILLIAM M. BRADSHAW AND WALTER G. MYLIUS, OF 'WILKINSBURG, PENNSYLVA- NIA, ASSIGNORS T0 WESTINGHOUSE ELECTRIC A CORPORATION OF PENNSYLVANIA.

REGULATOR SYSTEM FOR PULP GRINDERS.

Application filed July 20, 1922. Serial No. 576,401.

Our invention relates to regulator systems and it has special relation to load-regulating systems forv pulp grinders.

One object of our invention is to provide a system of the above-indicated character that shall embody means for maintaining a substantially constant load on the pulp grinder, said means being adapted to also prevent hunting action of said system.

Another object of our invention is to provide a hydraulic system of the above-indicated character which shall be responsive to variations in the pressure system for applying load to the grinder, as Well as to varia tions in load upon the grinder, and which shall be free from hunting action.

in some instances, it is desirable to drive a pulp grinder of a paper mill from a waterwheel, under which circumstances it may be preferable to employ a hydraulic system for maintaining a substantially constant load upon the pulp grinder. Devices having substantially this same object have been heretofore proposed but such devices have had the defect of operating with a hunting action. It is, therefore, an object of our invention to provide a new and improved hydraulically actuated regulator, the operation of which shall be free from hunting action.

Our invention will be best understood from the accompanying drawing, wherein the single figure is a diagrammatic illustration'of the apparatus of one embodiment of our invention.

Referring to the drawing, a pulp grinder 1 is adapted to be operated from a prime mover 2, such as a water-wheel, through a shaft 3. The wood or pulp a to be ground is adapted to be maintained in engagement with the stone of the pulp grindeu 1 through a fluid-pressure system that is supplied from a main supply pipe 5 through a lead-in pipe 6 and a valve mechanism 7 which may be of any well-known construction.

A regulator 8 is provided for maintaining the load upon the stone of the pulp grinder substantially constant throiwh the control of a Valve mechanism 9 whidh is located in the supply piping 11. Fluid is supplied to the valve mechanism 7 whenever the regulator becomes activeto control the load upon the grinder. The regulator 8 may be rendered ineffective by closing the valves 12 and 13 which are located in the piping 11 and opening the normally closed valve 14. Thereafter, the pressure upon the pulp 4 is determined by the manipulation of a reducing valve 15 which is located in the lead-in pipe 6. For the purposes of further discussion, it will be assumed that the valve 14 is closed and that the valves 12 and 13.are opened, thereby giving over the control to the regulator 8.

The regulator 8 comprises a floating lever 16 which has one end pivotally connected to the stem 17 of the valve mechanism 9, as indicated at 17', and has its other end pivotally connected to the connecting rod of a piston 18, as indicated at 18. Piston 18 co-operates with a cylinder 19. The connecting rod of a second piston 21 is pivotally con nected to an intermediate point of the lever 16, as indicated at 21. The piston 21 cooperates with a cylinder 22.

Fluid is admitted to the cylinder 19 beneath the piston 18 through piping 23 which is directly connected to the lead-in pipe 6 immediately ahead of the valve mechanism 7. The piping 23 is provided with any well-known form of bleeder valve,

indicated at 24.

Fluid, under pressure, is admitted to the cylinder 22 beneath the piston 21 through the pipe 26 from a centrifugal pump 25. The pipe 26 may be provided with any well known form of bleeder valve 27. The cen- AND MANUFACTURING COMPANY,

trifugal pump 25 is driven from the shaft" 3 of the pulp grinder 1 through the medium of chain 28 and co-operating sprocket wheels located upon the shaft 3 and the shaft of the centrifugal pump 25, respectively. Thus, the centrifugal pump 25 is operated in ac cordance with the speed of the pulp grinder 1, and, since the speed is directly dependent upon the load, it may be said that the pressure beneath the piston 21 is directly proportional to the speed of the pulp grinder, and to the load thereupon.

Mounted upon the stem of the piston 21 is a cross-bar 31 which has co-operating with the opposite ends thereof springs 32 and 2' Lee 33, which are attached to the cylinder 22 and are adjustable by means of screws 3d. The tension upon the springs 32 and determines the position of the valve 9 and therefore, the load upon the pulp grinder 1.

In the operation of the system, it the load upon the pulp grinder diminishes, the speed thereof will increase, thereby driving the centrifugal pump 25 more rapidly. This action will increase the pressure beneath the piston 21, thereby raising the same about the pivot 18, to open the valve 9 wider and increase the pressure upon the pulp grinder 1 to restore the load thereoi to normal.

By opening the valve 9 wider, the fluid pressure to the valve 7 is increased. This action also increases the pressure in the piping 23 leading to the cylinder 19, thereby raising the piston 18 about the pivot 21, and thus partially closing the valve 9. In this manner, the pressure upon the pulp l will be brought to that point where the pulp grinder is operating at the proper speed and with the proper load characteristics. The valve 7 will assume the proper position just prior to the obtaining of these characteristics, so that the completion of the corrective movement will be eilected without over-running ot' the regulator mechanism. Of course, the converse operation will be effected it there is an increase in load upon the pulp grinder 1.

Should the pressure in the supply line 5 decrease, there will likewise be a decrease in pressure in the piping 23 leading to the cylinder 19, so that the piston 18 will be lowered to open the valve 9, the lever 16 "moving about the pivot 21. Moreover, the

decreased pressure will decrease the load upon the pulp grinder so that the speed of the centrifugal pump 25 will be increased, as heretofore explained, to raise the piston 21, thereby operating the lever 16 about the pivot 18 to also open the valve 9. As the load upon the pulp grinder is restored to normal, the speed of the centrifugal pump 25 is lessened and the piston 21 is returned toward its normal position under the action of the springs 32 and 33, the position taken up by the valve 9 being that necessary to maintain the load upon the pulp grinder substantially constant. Likewise, the increased flow to the valve 7 will increase the pressure beneath the piston 18 to move the lever 16 about the pivot 21 to partially close the valve 9. The two devices co-operate to bring the valve 9 to its proper position just prior to the obtaining of normal load conditions in the system, so that there will be no hunting action.

Modifications in the system and arrangement and location or parts may be made within the spirit and scope of our invention, and such modifications are intended to be covered by the appended claims.

We claim as our invention 1. In a load-regulator system, the combination with a device the load upon which is to be maintained substantially constant and means for applying load thereto, of means for regulating the pressure in said system, said means being also adapted to prevent hunting action under all operative conditions.

2. In a load-regulator system, the combination with a pulp grinder, of means for maintaining the load upon said grinder substantially constant, said means being also adapted to prevent hunting action of said system under all operative conditions.

3. In a load-regulator system, the combination with a pulp grinder and a fluid-pressure system for applying load thereto, of hydraulically actuated means for regulating the pressure in said system and means for preventing hunting action under all operative conditions.

4-. In a load-regulator system, the combination with a pulp grinder and a fluid-pres sure system co-operating therewith, of means for maintaining the load upon said grinder substantially constant, said means being actuated in accordance with variations in said pressure system and in accordance with variations in the load upon said grinder, said means being also adapted to prevent hunting action or said system under all operative conditions.

5. In a regulator system, the combination with a pulp grinder and a fluid-pressure system for applying load thereto, of means "for regulating the load upon said grinder, said means comprising a floating lever, a valve mechanism connected thereto, means for initiating the action of said regulator in accordance with variations in pressure of said system, and means for initiating the action of said regulator mechanism in accordance with variations in speed of said pulp grinder, said means being adapted to co-operate to prevent hunting action in said system.

6. In a regulator system, the combination with a pulp grinder and a fluid-pressure system for applying load thereto, of regulator means for maintaining the load upon said grinder substantially constant, said regulator means comprising a floating lever and a valve mechanism connected thereto, and actuating means for said regulator comprising a centrifugal pump driven from the shaft of said pulp grinder, and a co-operating valve mechanism connected to said lever, the movements of the piston of which are varied by variations in the operation of said centrifugal pump.

7 In a regulator system, the combination with a pulp grinder and a fluid-pressure system for applying load thereto, and a main source of supply connected to said fluidpressure system, of automatic means for governing the pressure in said system to maintain the load upon said pulp grinder substantially constant, and means for rendering said regulator inactive and also adapted to thereafter determine the pressure in said system.

8. In a regulator system, the combination with a device, and means for applying load thereto, of fluid-pressure actuated means for controlling the load upon said device and means for preventing hunting action in said system under all operative conditions.

9. In a regulator system, the combination with a pulp grinder and a fluid-pressure system for applying load thereto, of regulator means for maintaining the load upon said grinder substantially constant, said regulator means comprising a floating lever and a valve mechanism connected thereto, and actuating means for said regulator comprising a centrifugal pump driven from the shaft of said pulp grinder and a co-operating valve mechanism connected to said lever, the movements of the piston of which are varied by variations in. the operation of said centrifugal pump, and means for preventing hunting action in said system.

10. In a regulator system, the combination with a device, a fluid-pressure system for applying load thereto, of regulator means for maintaining the load upon said device substantially constant, and hydraulic means for initiating the operation of said regulator means in accordance with variations in load upon said device.

11. In a regulator system, the combination with a device, a fluid-pressure system for applying load thereto, of regulator means for maintaining the load upon said device substantially constant, and hydraulic means for initiating the operation of said regulator means in accordance with variations in speed of said device.

12. In a regulator system, the combination with a device, a fluid-pressure system for applying load thereto, of regulator means for maintaining the load upon said de vice substantially constant, and hydraulic means for initiating the operation of said regulator means in accordance with variations in load upon said device, and antihunting means (to-operating therewith.

13. In a regulator system, the combination with a device, a fluid-pressure system for applying load thereto, of regulator means for maintaining the load upon said device substantially constant, and hydraulic means for initiating the operation of said regulator means in accordance with variations in speed of said device, and anti-hunting means co-operating therewith.

In testimony whereof, we have hereunto subscribed our names this 17th day of July, 1922.

WILLIAM M. BRADSHAW. WALTER G. MYLIUS. 

